The present invention relates to stretching and strengthening muscles of the lower leg of a human user, more specifically, stretching and strengthening muscles of the lower leg through eccentric, concentric, and optionally isometric contractions using a device that acts as a lever arm to generate the force required to effectively perform such contractions.
Physical therapy and other modalities focus on the use of biomechanically functional positions and leverage to isolate specific muscles in the body. Once isolated, the muscles can be strengthened and/or stretched using the three types of muscle contractions: (1) concentric (muscle shortens while generating force); (2) isometric (muscle maintains the same length while generating force); and (3) eccentric (muscle lengthens while generating force).
For most muscles, the leverage required to isolate and contract them is achieved simply by correctly positioning and manipulating the body. However, the human ankle joint is unique because the foot, which acts as a lever arm for the joint, is exceptionally short relative to the size of the muscles that both attach to it and cross the ankle joint. Thus, it is impossible for a therapist to generate the force required to effectively resist movement of the foot across the ankle joint. Consequently, a therapist is unable to assist the human user in performing the above types of muscle contractions. As a result, the most commonly-used method to stretch and strengthen the muscles of the back of the lower leg, or calf area, has been to place the toes on the edge of a step while hanging the heels off the edge to perform the three types of contractions.